Construction Of Biomolecule-functionalized Fluorescent Nanoparticles And Their Applications

Fluorescent nanoparticles have received immense popularity in recent years because of their attractive optical properties.In comparison to traditional organic dyes and fluorescent proteins,fluorescent nanoparticles offer much improved sensitivity and photostability.Furthermore,large surface-to-volume ratio and various chemical groups for subsequent modification of fluorescent nanoparticles offer a good platform for designing and fabricating multimodal/multifunctional nanoparticles.Moreover,these functionalized fluorescent nanoparticles are usually conjugated with tumour-targeted molecules and antitumor drugs,which can not only reach the target of curing some specific diseases,but also render the realtime tracking of the process of transport and function of these nanoparticles in biological systems.Therefore,it is possible for us to understand the biological behaviors at cellular or even molecular levels.In this thesis,we introduced the research work with two types of fluoresenct nanoparticles,CdTe/CdS/ZnS core/shell/shell quantum dots and graphene quantum dots.After functionalizing them with related chemical molecules,we introduced them into biological systems and performed several application tests.The details are as follows:Firstly,we used a microwave-assisted method to synthesize highly fluorescent CdTe/CdS/ZnS core/shell/shell quantum dots in aqueous solution and made a comprehensive study on the experimental parameters for the optimal protocol.Moreover,by the coating of inorganic ZnS shell and acetyl cysteine,CdTe/CdS/ZnS quantum dots overcame their intrinsic toxic behaviors,which could be directly incorporated into labelling of live cells.Secondly,with respect to the new-emerging graphene quantum dots in the family of graphene,we functionalized them with folic acids which could effectively recognize the overexpressed receptors on the surface of tumour cells and explored their specific recogntion to certain tumour cells.By loading an antitumour drug-doxorubicin on the system,we realized the selective drug-delivery to certain cancer cells.Thirdly,we established a multifunctional fluorescent nanosystem by conjugating graphene quantum dots with a DNA apatmer-AS1411.This system could simultaneously achieve targeted imaging,drug delivery,cancer treatment and auxiliary photothermal enhancement,while only two components were involved.This novel design will provided a new insight into the biological application of nanoparticles.In a word,in this thesis the fabrication and functionalization of two fluorescent nano probes were introduced in detail.Meanwhile,biological applications such as targeted drug delivery and cell imaging were achieved as a result,which lay a good foundation for the research and development of nanomaterials.